An arithmetic average or mean of a set of numbers is a single number around which the set seems to cluster.
The idea of average is not new to us. We are familiar with the following types of statements. ‘My average on test is 96%, “Gavaskar averaged 57 runs in the series.”
The average is also called the Mean
Average =(Sum of observations/Number of observations)
Average MCQ’s
Results
#1. Find the average of all the numbers between 6 and 34 which are divisible by 5.
Find the average of all the numbers between 6 and 34 which are divisible by 5.
Average=(10 15 20 25 30/5
= 100/5
20
#2. Find the average of all prime numbers between 30 and 60
Find the average of all prime numbers between 30 and 60
There are 5 prime numbers between 30 and 50
They are 31,37,41,43, and 47
Average = (31 37 41 43 47/5)
= 199/5
=39.8
#3. The average of first five multiple of 3 is :
The average of first five multiple of 3 is :
average=3(1 2 3 4 5)/5
=45/5
=9
#4. The average of four consecutive even numbers is 27. Find the largest of these numbers.
The average of four consecutive even numbers is 27. Find the largest of these numbers.
Let the numbers be x, x 2, x 4 and x 6. then
x (x 2) (x 4) (x 6)/4=27
4x 12/4=27
x 3=27
x=24
Largest number=(x 6)= 24 6=30
#5. A batsman makes a score of 87 runs in the 17th inning and thus increases his averages by 3. Find his average 17th inning
A batsman makes a score of 87 runs in the 17th inning and thus increases his averages by 3. Find his average 17th inning
Let the average after 17th inning = x
Then average after 17th inning = (x-3)
16(x-3) 87=17x
x=(87-48)
=39
#6. The average of the first nine prime number is :
The average of the first nine prime number is :
average = (2 3 5 7 11 13 17 19 23/9)
= 100/9
=11¹/₉
#7. The average of 2, 7, 6 and x is 5 and the average of 18, 1, 6, x and y is 10. What is the value of y?
The average of 2, 7, 6 and x is 5 and the average of 18, 1, 6, x and y is 10. What is the value of y?
We have : (2 7 6 x/4)=5
15 x=5*4
15 x=20
x=20-15
x=5
also, (18 1 6 x y/5)=10
25 5 y=50
30 y=50
y=50-30
y=20
#8. If the mean of a,b,c is M and ab+bc+ca= 0, then the mean of a²,b²,c² is :
If the mean of a,b,c is M and ab bc ca= 0, then the mean of a²,b²,c² is :
We have : (a b c/3)=M
(a b c)=3M
Now, (a b c)² = (3M)²
=9M²
a² b² c² 2(ab bc ca)=9M²
a² b² c²=9M²
required mean = (a² b² c²/3)
=9M²/3
=3M²
#9. The average of a non-zero number and is square is five times the number, the number is :
The average of a non-zero number and is square is five times the number, the number is :
number the be x then
x x²/2=5x
x²-9x=0
x(x-9)=0
x=0
x=9
so , the number is 9
#10. The average of 7 consecutive number is 20 the largest of these number is :
The average of 7 consecutive number is 20 the largest of these number is :
the number be x,x 1,x 2, x 3,x 4,x 5 and x 6
then x (x 1) (x 2) ( x 3) (x 4) (x 5) (x 6)/7=20
7x 21=140 or 7x= 119 or x=17
largest number = x 6=23
#11. The average of 50 numbers is 30. If two numbers, 35 and 40 are discarded, then the average of remaining number is nearly
The average of 50 numbers is 30. If two numbers, 35 and 40 are discarded, then the average of remaining number is nearly
sum of 50 number = 30*50=1500
sum of remaining 48 numbers = 1500 -(35 40 )
=1425
average = (1425/ 48)
=29.68
#12. The average score of cricketer for ten matches is 38.9 runs. If the average for the first 6 matches is 42. Then find the average for the last four matches
The average score of cricketer for ten matches is 38.9 runs. If the average for the first 6 matches is 42. Then find the average for the last four matches
average = (38.9*10)- (42*6)/4
=137/4
=34.25
#13. The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is :
The mean of 50 observations was 36. It was found later that an observation 48 was wrongly taken as 23. The corrected new mean is :
Correct sum = ( 36*50 48-23)=1825
correct mean = 1825 /50
=36.5
#14. Average of 10 positive number is x' if each number is increase by 10% then x' :
Average of 10 positive number is x’ if each number is increase by 10% then x’ :
x₁ x₂ ……….. x₁₀/ 10= x’
x₁ x₂ ……….. x₁₀ = 10x’
110/100 x₁ 110/100 x₂ …… 110/100 x₁₀ = 110/100*10X’
110/100 x₁ 110/100 x₂ …… 110/100 x₁₀/10=11/10X’
Average is increases by 10 %